The secretory cells of the primate oviduct synthesize and secrete an estrogen-dependent oviduct-specific 120 kDa glycoprotein (OGP). OGP is the major nonserum protein present in the oviductal lumen at the time of ovulation, fertilization and early embryonic development. OGP can be purified from oviductal explant culture medium, but a richer source of OGP is oviductal fluid. In order to obtain significant quantities of OGP for functional studies, we have developed a method for collecting oviductal fluid. Two adult monkeys were ovariectomized and a polyurethane cannula (Access Tech., Skokie, IL) was installed into each oviduct. Each cannula was connected to a subcutaneous port (V-A-P Access Port Model TI200, Access Tech.). The monkeys were then treated sequentially with estradiol (E2) and progesterone (P) to create artificial menstrual cycles with a prolonged follicular (E2-primed) phase. Briefly, a 3 cm Silastic capsule packed with crystalline E2 was inserted s.c. into the monkeys for 8 weeks. After 8 weeks of E2-priming, a 6 cm Silastic capsule containing crystalline progesterone was inserted s.c. for 14 days to create an artificial luteal phase. After 14 days of E2 plus P treatment the E2 and P implants were removed, and a new E2 capsule was replaced to complete the cycle. Oviductal fluid was collected via the subcutaneous ports at 3-4 day intervals during each extended 8-week follicular phase. The monkeys were allowed to rest during each 14-day luteal phase. Mean volume of fluid collected per oviduct was 172 q 21 ul per collection during the first collection period and remained in the 50-200 ul range throughout the study. Western blot analysis of oviductal fluid revealed abundant OGP in samples collected during the follicular phase. We are currently developing methods for immunopurifying OGP from these samples. In summary, we have established a reliable method for the long-term harvest of oviductal fluid for purification of OGP.